Saturday, February 27, 2010

Textiles review: fiber properties & serviceability concepts

The first test of the semester in my textiles class is rapidly approaching. I have attended every lecture and lab, done all my homework, taken meticulous notes, and kept up with all the readings, and still I am worried. There is a lot I need to know. The professor gave us a study guide for the test, but she could have conveyed the same information by simply saying, “Memorize chapters one through seven.” I decided to summarize the important concepts in a blog entry. I expect doing so will help me retain this information, and perhaps some of you will find it useful and interesting too.

Chapter 1 – Introduction to textiles

Fiber – any substance with a high length to width ratio and suitable characteristics for being processed into a fabric. Fibers are the smallest components of a fabric.

Yarn – an assemblage of fibers twisted or laid together to make a continuous strand.

Fabric – a flexible planar substance constructed from solutions, fibers, yarns, or fabrics, in any combination.

Gray (grey, greige) goods – an unfinished fabric.

Finish – any process used to add color and enhance performance of gray goods.

Textile (textbook definition) – this term originally meant woven fabrics, but it is now used to refer to fibers and anything made out of fibers.

Textile (lecture definition) – fiber + yarn + structure + finish = textile. Gray goods are unfinished. Felt is made without yarn.

Chapter 2 – Serviceability concepts
Serviceability is a measure of a textile product’s ability to meet the specific needs of a customer. There are eight serviceability concepts used to describe a textile’s performance. These concepts do not describe a textile as good or bad, rather they allow a customer to understand how a textile will perform in specific situations. A textile that may be great in one environment may be terrible in another. For example, wool has excellent thermal retention, so a wool sweater that is comfortable in winter is uncomfortable in summer.

The eight serviceability concepts are aesthetics, durability, comfort, safety, appearance retention, care, environmental impact, and cost. The terms in italics after the definitions are fiber properties that relate to each concept. The properties will be defined in the next section.

Aesthetics – attractiveness/appearance of a textile. How it looks. Luster, drape, texture, hand, dyeability

Durability – the manner in which a textile withstands use. The length of time a product remains usable for the purpose for which it was intended. Abrasion resistance, flexibility, tenacity, elongation, sunlight resistance, moth resistance, mildew resistance

Comfort – the way a textile affects heat, air, and moisture transfer. How it feels to the body. Absorbency, heat conductivity, density, electrical conductivity, wicking

Safety – a textile’s ability to protect a body from harm. Tenacity, absorbency, heat conductivity, heat sensitivity, flammability

Appearance retention – how the product maintains its original appearance. Resiliency, dimensional stability, shrinkage resistance, elasticity, loft, sunlight resistance, pilling

Care – the treatment required to maintain a textile product’s original appearance and cleanliness. Moth resistance, heat resistance, mildew resistance, chemical reactivity, shrinkage resistance

Environmental impact – effects of production, use, care, and disposal of a textile product.

Cost – amount paid to acquire, use, maintain, and dispose of a textile product.

Chapter 3 – fibers and fiber properties
Fibers may be classed as natural or manufactured. Natural fibers grow in nature in recognizable fiber form. They come directly from plants (cellulosic fibers) or animals (protein fibers). Manufactured fibers are formed into fibers from chemical compounds. They do not exist in fiber form without human intervention. Manufactured fibers may be regenerated or synthetic. Regenerated fibers are produced from naturally occurring polymers that do not occur naturally as fibers. Regenerated fibers are made from cellulose (plant) or protein (plant or animal). Synthetic fibers are made from polymers that do not occur naturally. Most synthetic fibers are made from petrochemicals.

The properties of a fiber, yarn properties, fabric construction, and finish contribute to the properties of a fabric. The physical structure, chemical composition, and molecular arrangement of a fiber determine its serviceability properties.

Length is the measurement of the length of a fiber used to make yarns. Staple fibers are short fibers measured in inches or centimeters. Staple fibers range in length from less than one inch to approximately 18 inches. Except for silk, all natural fibers are available only as staple fibers. Filament fibers are long, continuous fibers measured in miles or kilometers. Silk and manufactured fibers may be either staple or filament.

A fiber’s diameter is measured in micrometers. Natural fibers are subject to growth irregularities that affect their diameter. The diameter of manufactured fibers is controlled during production.

Denier is the weight in grams of 9,000 meters of a fiber or yarn.

Fibers may be solid or hollow. Their surfaces may be smooth or textured. The cross sectional shape and surface contour of natural fibers is a result of how the fibers grow. The shape and surface contour of manufactured fibers is controlled during production.

Crimp is twists, curls, or coils along the length of a fiber. Crimp affects hand, cohesiveness, resiliency, stretch, bulk, heat retention, abrasion resistance, and absorbency. Crimp exists naturally in wool, and it can be added to manufactured fibers.

Properties:

Abrasion resistance is a fiber’s ability to resist damage from rubbing.

Absorbency (or moisture regain) is a fiber’s ability to take up moisture.

Chemical reactivity describes how a fiber responds to specific chemicals such as acids, alkalis, oxidizing agents, and solvents.

Density (or specific gravity) is the measure of the mass of a fiber per cubic centimeter. Specific gravity is the ratio of a fiber’s density to that of water (which has a density of 1g/cc at 4oC). Fibers with a specific gravity less than 1 float, while those whose specific gravity is greater than 1 sink.

Dimensional stability describes a fiber’s ability to retain a size and shape.

Drape describes how a fiber hangs over a three dimensional form.

Dyeability is a fiber’s ability to take up and retain dyes.

Elasticity is the ability of a fiber to return immediately to its original length.

Electrical conductivity is the ability of a fiber to transfer electrical current. Fibers with high electrical conductivity do not develop a static charge.

Elongation measures how much a fiber may be stretched without breaking.

Flammability is a fiber’s ability to burn. It describes how the fiber reacts to ignition sources, and at what temperature the fiber will ignite (if it is inflammable).

Hand describes how a fiber feels. Is it smooth, harsh, silky, dry, clammy, etc.?

Heat conductivity (or thermal retention) is the ability of a fiber to retain or transfer heat. It describes the insulation properties of a fiber. Fibers with low heat conductivity (high thermal retention) are good insulators.

Heat sensitivity describes how a fiber reacts to high heat. Does it shrink, soften, melt, discolor, or ignite if exposed to high heat, and at what temperature will it do so?

Loft is the ability of a fiber to spring back to its original thickness after being compressed.

Luster is the amount of light reflected from the surface of a fiber.

Mildew resistance describes a fiber’s ability to resist the growth of mildew, mold, and fungus.

Moth resistance is a fiber’s resistance to insect damage. It describes which insects (if any) will eat the fiber.

Pilling is the formation of balls of fiber (pills) on the surface of a fabric.

Resiliency is a fiber’s ability to return to its original shape after bending, twisting, and crushing. Fibers with high resiliency resist wrinkling.

Shrinkage resistance is a fiber’s ability to retain its original size through use and care.

Sunlight resistance is a fiber’s ability to withstand damage and discoloration from sunlight.

Tenacity is a fiber’s strength measured in grams per denier. The breaking tenacity of a fiber is the force required to break the fiber. Moisture affects a fiber’s tenacity, so the breaking tenacity is measured both dry and wet.

Texture is the nature of a fiber or fabric surface. It describes the way a fiber or fabric appears.

1 comment:

  1. How about a woven basket for your knitting projects or the beach. These are from Lantern Moon.




    Colored Regenerated Yarns

    ReplyDelete